1,143 research outputs found

    Domain walls in three dimensional gauged supergravity

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    We explicitly construct two Chern-Simons gauged supergravities in three dimensions with N=4 and N=8 supersymmetries and non-semisimple gauge groups. The N=4 theory has scalar manifold SO(4,3)/SO(4)×SO(3)SO(4,3)/SO(4)\times SO(3) with the gauge group SO(3)(T3,T^3)SO(3)\ltimes (\mathbf{T}^3,\hat{\mathbf{T}}^3). The theory describes (1,0) six dimensional supergravity reduced on an SU(2) group manifold. The equivalent Yang-Mills type gauged supergravity has SO(3) gauge group coupled to three massive vector fields. The N=8 theory is described by SO(8,8)/SO(8)×SO(8)SO(8,8)/SO(8)\times SO(8) scalar manifold, and the gauge group is given by SO(8)T28SO(8)\ltimes \mathbf{T}^{28}. The theory is a truncation of the SO(8)T28SO(8)\ltimes \mathbf{T}^{28} gauged N=16 theory with scalar manifold E8(8)/SO(16)E_{8(8)}/SO(16) and can be obtained by an S^7 compactification of type I theory in ten dimensions. Domain wall solutions of both gauged supergravities are analytically found and can be uplifted to higher dimensions. These provide domain wall vacua in the three dimensional gauged supergravity framework which might be useful for the study of Domain Wall3_3/QFT2_2 correspondence.Comment: 19 pages, no figures, typoes and a mistake in a sign corrected, clarifications on the notations adde

    Conducting Research with Stigmatized Populations: Practices, Challenges, and Lessons Learned

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    Conducting research with communities who are at risk of being stigmatized can be a challenging endeavor. It is often difficult to reach and recruit individuals for research purposes regarding a stigmatized condition or situation. Yet, researchers in our field have recognized the importance of work in this area and have individually developed a range of strategies to reach, recruit, and work with these populations. This workshop will invite researchers and practitioners to present, discuss, and compare strategies and experiences when working with stigmatized communities in the context of the ever-evolving nature of technology. The outcomes of the workshop will include an outline for an article that will summarize the strategies and practices discussed as well as identify the approaches that have led to the best outcomes across different populations

    Participatory analysis for adaptation to climate change in Mediterranean agricultural systems: possible choices in process design (versão Pre Print)

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    There is an increasing call for local measures to adapt to climate change, based on foresight analyses in collaboration with actors. However, such analyses involve many challenges, particularly because the actors concerned may not consider climate change to be an urgent concern. This paper examines the methodological choices made by three research teams in the design and implementation of participatory foresight analyses to explore agricultural and water management options for adaptation to climate change. Case studies were conducted in coastal areas of France, Morocco, and Portugal where the groundwater is intensively used for irrigation, the aquifers are at risk or are currently overexploited, and a serious agricultural crisis is underway. When designing the participatory processes, the researchers had to address four main issues: whether to avoid or prepare dialogue between actors whose relations may be limited or tense; how to select participants and get them involved; how to facilitate discussion of issues that the actors may not initially consider to be of great concern; and finally, how to design and use scenarios. In each case, most of the invited actors responded and met to discuss and evaluate a series of scenarios. Strategies were discussed at different levels, from farming practices to aquifer management. It was shown that such participatory analyses can be implemented in situations which may initially appear to be unfavourable. This was made possible by the flexibility in the methodological choices, in particular the possibility of framing the climate change issue in a broader agenda for discussion with the actors

    Monitoring Cognitive and Emotional Processes Through Pupil and Cardiac Response During Dynamic Versus Logical Task

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    The paper deals with the links between physiological measurements and cognitive and emotional functioning. As long as the operator is a key agent in charge of complex systems, the definition of metrics able to predict his performance is a great challenge. The measurement of the physiological state is a very promising way but a very acute comprehension is required; in particular few studies compare autonomous nervous system reactivity according to specific cognitive processes during task performance and task related psychological stress is often ignored. We compared physiological parameters recorded on 24 healthy subjects facing two neuropsychological tasks: a dynamic task that require problem solving in a world that continually evolves over time and a logical task representative of cognitive processes performed by operators facing everyday problem solving. Results showed that the mean pupil diameter change was higher during the dynamic task; conversely, the heart rate was more elevated during the logical task. Finally, the systolic blood pressure seemed to be strongly sensitive to psychological stress. A better taking into account of the precise influence of a given cognitive activity and both workload and related task-induced psychological stress during task performance is a promising way to better monitor operators in complex working situations to detect mental overload or pejorative stress factor of error

    The relationship between smokers' motivation to quit and intensity of tobacco control at the population level: a comparison of five European countries

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    Background: Smoking prevalence differs significantly across Europe. In addition, there are considerable differences in tobacco control activities across European countries. The relationship between prevalence and policy is under-researched. The present analysis examines the motivation to change smoking behaviour across 5 different European countries that differ considerably in their tobacco control activities. Methods: A population-based, representative survey of 1750 smokers, aged 16–59, from 5 different European countries (Germany, Greece, Poland, Sweden, UK) was used. Demographic variables, smoking status and the motivation to stop smoking were assessed. Motivation was assessed as, first, intending to quit (using the stages of change plus a modified stage for Precontemplation), and second, the desire to quit. Results: The majority of smokers want to stop smoking (73.5%), while only 35.0% want to stop definitely. Across countries, 10.2% definitely do not want to stop. Most of the smokers can be categorised in the Precontemplation stage (between 62.6% and 77.7% depending on the country), one of the stages of change categories. The relationship between the stages of change and the country under examination is statistically significant (chi-square = 43.466, p < 0.001). In countries with a high level of tobacco control, the proportion of people in Precontemplation is lower than in countries with low tobacco control activity. Conclusion: There are differences in the stages of change between the countries under examination. However, the categorisation of the countries into low, medium and high tobacco control activity used in this analysis does not explain these differences. Most smokers want to stop smoking, but a high proportion cannot indicate a time-frame when this is going to happen. Tobacco control efforts or other kinds of support might encourage these smokers to actually try to stop. Longitudinal studies at the population level are needed to assess, relate or monitor tobacco control activities and the intention to stop

    Neurochemical Changes in the Mouse Hippocampus Underlying the Antidepressant Effect of Genetic Deletion of P2X7 Receptors.

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    Recent investigations have revealed that the genetic deletion of P2X7 receptors (P2rx7) results in an antidepressant phenotype in mice. However, the link between the deficiency of P2rx7 and changes in behavior has not yet been explored. In the present study, we studied the effect of genetic deletion of P2rx7 on neurochemical changes in the hippocampus that might underlie the antidepressant phenotype. P2X7 receptor deficient mice (P2rx7-/-) displayed decreased immobility in the tail suspension test (TST) and an attenuated anhedonia response in the sucrose preference test (SPT) following bacterial endotoxin (LPS) challenge. The attenuated anhedonia was reproduced through systemic treatments with P2rx7 antagonists. The activation of P2rx7 resulted in the concentration-dependent release of [3H]glutamate in P2rx7+/+ but not P2rx7-/- mice, and the NR2B subunit mRNA and protein was upregulated in the hippocampus of P2rx7-/- mice. The brain-derived neurotrophic factor (BDNF) expression was higher in saline but not LPS-treated P2rx7-/- mice; the P2rx7 antagonist Brilliant blue G elevated and the P2rx7 agonist benzoylbenzoyl ATP (BzATP) reduced BDNF level. This effect was dependent on the activation of NMDA and non-NMDA receptors but not on Group I metabotropic glutamate receptors (mGluR1,5). An increased 5-bromo-2-deoxyuridine (BrdU) incorporation was also observed in the dentate gyrus derived from P2rx7-/- mice. Basal level of 5-HT was increased, whereas the 5HIAA/5-HT ratio was lower in the hippocampus of P2rx7-/- mice, which accompanied the increased uptake of [3H]5-HT and an elevated number of [3H]citalopram binding sites. The LPS-induced elevation of 5-HT level was absent in P2rx7-/- mice. In conclusion there are several potential mechanisms for the antidepressant phenotype of P2rx7-/- mice, such as the absence of P2rx7-mediated glutamate release, elevated basal BDNF production, enhanced neurogenesis and increased 5-HT bioavailability in the hippocampus

    A Connection between Colony Biomass and Death in Caribbean Reef-Building Corals

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    Increased sea-surface temperatures linked to warming climate threaten coral reef ecosystems globally. To better understand how corals and their endosymbiotic dinoflagellates (Symbiodinium spp.) respond to environmental change, tissue biomass and Symbiodinium density of seven coral species were measured on various reefs approximately every four months for up to thirteen years in the Upper Florida Keys, United States (1994–2007), eleven years in the Exuma Cays, Bahamas (1995–2006), and four years in Puerto Morelos, Mexico (2003–2007). For six out of seven coral species, tissue biomass correlated with Symbiodinium density. Within a particular coral species, tissue biomasses and Symbiodinium densities varied regionally according to the following trends: Mexico≥Florida Keys≥Bahamas. Average tissue biomasses and symbiont cell densities were generally higher in shallow habitats (1–4 m) compared to deeper-dwelling conspecifics (12–15 m). Most colonies that were sampled displayed seasonal fluctuations in biomass and endosymbiont density related to annual temperature variations. During the bleaching episodes of 1998 and 2005, five out of seven species that were exposed to unusually high temperatures exhibited significant decreases in symbiotic algae that, in certain cases, preceded further decreases in tissue biomass. Following bleaching, Montastraea spp. colonies with low relative biomass levels died, whereas colonies with higher biomass levels survived. Bleaching- or disease-associated mortality was also observed in Acropora cervicornis colonies; compared to A. palmata, all A. cervicornis colonies experienced low biomass values. Such patterns suggest that Montastraea spp. and possibly other coral species with relatively low biomass experience increased susceptibility to death following bleaching or other stressors than do conspecifics with higher tissue biomass levels

    The Hide-and-Seek of Grain Boundaries from Moire Pattern Fringe of Two-Dimensional Graphene

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    Grain boundaries (GBs) commonly exist in crystalline materials and affect various properties of materials. The facile identification of GBs is one of the significant requirements for systematical study of polycrystalline materials including recently emerging two-dimensional materials. Previous observations of GBs have been performed by various tools including high resolution transmission electron microscopy. However, a method to easily identify GBs, especially in the case of low-angle GBs, has not yet been well established. In this paper, we choose graphene bilayers with a GB as a model system and investigate the effects of interlayer rotations to the identification of GBs. We provide a critical condition between adjacent moire fringe spacings, which determines the possibility of GB recognition. In addition, for monolayer graphene with a grain boundary, we demonstrate that low-angle GBs can be distinguished easily by inducing moire patterns deliberately with an artificial reference overlayopen0
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